1. Field of the Invention
The principal of photoparametric amplification has been applied to arrays of photodiodes, primarily silicon photodiodes. A problem arises however, in applying this principal to photodiode arrays in which the diodes are formed on a common substrate in that they require a common cathode.
In such case, pumping the photodiode simultaneously makes it impossible to determine from which diode a mixed signal originates.
2. Description of the Prior Art
FIG. 1 illustrates the basic photoparamp circuit. An intensity-modulated light signal is mixed with the pump frequency in the photodiodes, producing sum and difference signals at the output of the demodulator. The original signal frequency, amplified, is then recovered at the output of the demodulator.